Orion 52083 - Manual (Page 20)

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To take dark frames for subtraction from “light” images:
1. In the Camera Control Window, set the Mode to Dark 1x1.
2. Set the exposure time to whatever you set it to (or will set it to) for taking
actual (“light”) images.
Note: When taking dark frames, do not change any of the settings in the Setup
button from what they were (or will be) when “light” images are taken.
3. In the box beneath the Mode box, choose Autosave. Now set the number of
dark frames you would like the camera to take under Autosave (3 to 10 will
generally suffice, as these will be averaged together), select the file folder
in which you would like to save the dark frames with Folder, and enter in a
Base filename for the captured dark frames. Typically the name of the object
being imaged with the word “dark” added, such as “OrionNebula1dark”,
will be entered here. If “OrionNebula1dark” is the Base filename, and
you choose to Autosave five images, then the images will appear in the
selected file folder as “OrionNebula1dark_0001.fit”, “OrionNebula1dark_
0002.fit”, “OrionNebula1dark_0003.fit”, “OrionNebula1dark_0004.fit”, and
“OrionNebula1dark_0005.fit”. Using the word “dark” in the Base filename
will help you distinguish between light and dark frames when combining
later.
4. Click Expose, and Maxim DL Essentials will indicate the camera needs to
be covered to take a dark frame. Cover the front of the lens you are imaging
through, and then click OK. The camera will commence taking and saving
the dark frames.
Now that you have acquired several dark frames, combine them into a single
averaged dark frame for subtraction from “light” images:
5. In the Process menu, select Setup Dark Subtract.
6. In the window that pops-up, click Remove All if any filenames appear in
the window.
7. Click Add, and select the file folder location for the dark frames taken.
Select the dark frames and click Open.
8. The selected dark frames will now appear in the pop-up window. Click OK.
The dark frames have now been averaged and stored into memory.
You are now ready to subtract the averaged dark frame from “light” images.
This should be done to individual light images BEFORE combining them
together. There are two ways to do this. If you take dark frames first, before
taking light images (using Light 1x1), then you can automatically subtract the
averaged dark frame from each individual light image as it is captured. If you
take dark frames after you have already taken the light images (using Light
1x1), then you can subtract the averaged dark frame from each individual
image before you combine them into a single, final resultant image.